Apparatus for driving and lining tunnels in unstable soil



Nov. 7, 1967 K. STURM APPARATUS FOR DRIVING AND LINING TUNNELS FiledMarch 25, 1965 '[N UNSTABLE SOIL 5 Sheets-Sheet 1' FIG.

5 Sheets-Sheet 2 Nov. 7, 1967 K. STURM v APPARATUS FOR DRIVING ANDLINING TUNNELS IN UNSTABLE SOIL 7 Filed March 25, 1965 A m M o: l

i A A K. STURM Nov. 7, 1967 APPARATUS FOR DRIVING AND LINING TUNNELS INUNSTABLE SOIL Filed March 25, 1965 '5 Sheets-Sheet 3 K. STURM APPARATUSFOR DRIVING AND LINING TUNNELS IN UNSTABLE SOIL 5 Sheets-Sheet 4 Nov. 7,1967 Filed March 25, 1965 FIG. 5

Nov. 7, 196

K. STURM APPARATUS FOR DRIVING AND LINING TUNNELJS IN UNSTABLE SOILFiled March 25, 1965 5 Sheets-$heet 5 FIG. 7

United States Patent 3,350,889 APPARATUS FOR DRIVING AND LINING T UNNELSIN UNSTABLE SOIL Karl Sturm, 499 Ventura Crescent, North Vancouver,British Columbia, Canada Filed Mar. 25, 1965, Ser. No. 442,677 Claimspriority, application Canada, Apr. 15, 1964, 900,389, Patent 715,426 18Claims. (Cl. 6185) ABSTRACT OF THE DISCLOSURE An apparatus for drivingand concrete lining a tunnel in unstable ground, even in the presence ofwater, in a continuous operation without the aid of permanentlyinstalled supports and without pressurizing the tunnel itself, therebyreducing the hazardous conditions during tunnel driving and providing amore economical and efficient operation. This can be achieved by thedescribed apparatus which consists of three distinct sections. The frontsection comprises the excavation arrangement having a closed shield nearits forward end which permits the application of compressed air againstthe excavated face without pressurizing the tunnel itself, and whichalso supports various mining equipment operated from the rear andextending through the shield. Therefore, no personnel is exposed tocompressed air. The second section constitutes a sliding temporarysupport for the surrounding soil and extends to the front face of theconcrete lining. The soil on the inside of the tunnel is therefore neverexposed to atmospheric pressure and its internal stress pattern isalways preserved. A temporary support, permanently installed, in form ofsteel ribs or plates is not required. The third section comprises aslip-form for the concrete lining and has provision for steam curing toaccelerate the strength gain of the concrete, thus allowing thereduction of the physical length of the apparatus. The slip-form isarranged to permit the insertion of reinforcement and other structuralcomponents. The loosened material from the tunnel face is transportedhydraulically in closed pipes from the excavation face directly to thedisposal area outside the tunnel. The tunnel therefore is free for theuse of other operations. The concrete is placed by means of concretepumps in a nearly continuous operation.

The invention relates to an improved method and apparatus for boring andlining of tunnels in soil, soft rock and water bearing strata.

When driving tunnels in soil or soft rock it is generally necessary tosupport the entire bore hole simultaneously with the excavation. Thisentails the use of specially formed supports made of steel, cast-iron orprecast concrete, behind which grout or concrete is placed. In the caseof tunnelling in water bearing strata, it is necessary to prevent soiland water from flowing into the bore hole. With present methods andequipment, this is commonly achieved by the use of a protective shieldand by pressurizing the tunnel or alternatively by stabilizing theground by freezing, grouting or chemical processes. Although theseconstruction methods work effectively, they have the disadvantages ofbeing slow, inefiicient, very expensive and hazardous to life, in thatmen must work in the pressurized tunnel and at the exposed excavationface.

It is the object of this invention to overcome these disadvantages byproviding an apparatus and method which will make it possible to driveand line a tunnel of any size and shape through unstable soil and softrock, even in the presence of ground water, in a continuous operation,without the aid of permanently installed supports and withoutpressurizing the tunnel itself, thereby reducing showing details of theI plates 16 and stiffener rings 17 are rigidly 3,350,889 Patented Nov.7, 1967 the hazardous conditions and providing a more economical andefficient operation. This can be achieved by a tunnelling machine havinga shield close to its forward end which permits the application ofpressure against the excavated face without pressurizing the tunnelitself. The tunnelling machine is provided with conventional excavatingequipment capable of operating in front of the shield and with suitablemeans for hydraulically removing the loosened material from theexcavation chamber. The rear end of the tunnelling machine serves as acontinuous slipform for the concrete tunnel lining and is so equipped topermit high pressure steam curing of the concrete. Advancement of themachine in the tunnel is accomplished by a number of jacking mechanismsacting against the forward face of the concrete lining and aiding in thecon solidation of the freshly placed concrete.

For practical application the tunnelling machine may be convenientlydivided into three distinct parts, namely: the front part, consisting ofthe leading tube and shield, mining equipment and pump sump; theintermediate part, consisting of the second tube, bulkhead, outerslipform and jacking mechanism; the rear part, consisting of the thirdtube, inner slip-form and steam curing provisions.

These and other parts of the invention appear from time to time as thefollowing specification proceeds and the advantages and objects of theinvention became apparent by referring to the accompanying drawingswhere- 111 FIGURE 1 is a longitudinal section of the front andintermediate parts of the tunnelling machine, showing the generalarrangements for excavation, tunnel advancement, forming and concreting.

FIGURE 2 is a longitudinal section of the intermediate and rear parts ofthe tunnelling machine, showing the concrete steam curing and excavationdisposal pipe arrangements.

FIGURE 3 is a cross-section through the leading tube, showing thearrangement of the front face of the shield.

FIGURE 4 is a crosssection through the leading tube, showing thearrangement of the rear face of the shield.

FIGURE 5 is a cross'section through the second tube, showing thearrangement of the slip-form and bulkhead.

FIGURE 6 is a cross-section through the third tube, showing thearrangement of the slip-form and steam curing pI'OVlSlOIlS.

FIGURE 7 is a section through the bulkhead ring,

rubber air valve. FIGURE 8 is a section through the third tube, showingdetails of the cleaning chamber adjacent to the concrete curing portionof the slip-form.

In the embodiment of the invention illustrated in the drawings, thetunnelling machine is shown as having a leading tube 11 at the front, anintermediate tube 12 in the middle and a third tube or inner slip-form13 extend ing a substantial distance rearwards into the concrete linedsection of the tunnel.

The leading tube 11 extends from its cutting edge 14 to its tail end 15and is made out of strong durable material like steel, the outside shapeof which conforms exactly to the outside dimensions of the tunnellining. Stilfener connected to the leading tube 11 to provide additionalstrength. Attached to one of these stiffener rings 17 by means of bolts19 or conventional quick couplings is a removable shield 18 having anopening 20 through which excavated material passes into the dischargeline 21 and an opening 22 through jacks 26 from an open position to aclosed position, where it bears against rubber sealstrips 27.

The mining equipment 23 is of commercially known type used for rotaryand percussion drilling and consists of a motor 28, which is moved onguides 29 by means of chains 31 driven by an airmotor 30. The drillingrod 32 is connected to the motor 28 by conventional type couplings andextends through the ball joint 33 to the excavation face. At the forwardend of the drilling rod a cutter 34 or drilling bit is attached.Alternatively, suitable hydraulic jetting equipment can be attached tothe drilling rod where the material to be excavated suggests the use ofsuch equipment. The ball joint 33 has a hole 35 through its centre withprovision for the installation of seal rings 36 and bushings 37. Theball 33 is contained by a split shell 38, which can be rotated around anaxis perpendicular to the shield 18 which also serves as a cover to thehole 22. The guide plate 39 has provision for the insertion of seal ring40. The split shell 38 is so shaped to allow rotation of the drillingrod through an angle of approximately 70 degrees from the centre line toone side only, thereby providing a better sealed joint. To allow thecutter 34 to reach every part of the excavation face the ball joint 33is rotated as previously mentioned by an open chain 45 attached to asprocket 44 which is turned by hydraulic jacks 43. The ends of the openchain 45 are slung around the ball joint 33 and are fastened thereto bymeans of pins for easier disconnection. The supports 46 of the hydraulicjacks 43 are held in place by pins 47 to allow for angular movement whenthe sprocket 44 is being rotated.

The mining equipment 23 and guides 29 are connected to the split shell38 by a pin 41 which allows for rotation of the said equipment whenactuated by the hydraulic jacks 42.

To allow the removal or exchange of the drilling tools, the rod 32 isretracted until the bit 34 touches the ball joint, after which the cover24 is lowered and enclosed space depressurized by opening the valves atthe pipes 48. The chain 45 is then disconnected and the guide plate 39removed together with the entire mining equipment. Installation ofequipment is performedin a reverse sequence.

A crusher 49 of commercially known type is attached to the rear of theshield 18 behind the opening and in line with the discharge line 21.This crusher is driven by motor 50 through a gear or belt transmission51 and a flexible coupling 52 and reduces small boulders and oversizedgravel to a size suitable for conveyance hydraulically along thedischarge line. Air or water lines are connected to nozzles 53 (FIGURES3 and 4) located at the bottom of the shield 18 to allow the accumulatedloosened material in front of the opening 20 to be agitated as and whennecessary for easier discharge into the crusher 49. The shield 18 isalso furnished with removable windows 54 capable of withstanding highpressure and nozzles 56, installed at the highest possible location, toregulate the supply of compressed air to the excavation chamber.Adjustable spotlights 57, behind heavy duty glass, provide light forinspection of conditions in the chamber. All windows 54 and lights 57are furnished with nozzle type window washers 60 and lids 129. A manhole58, complete with inspection window 54, is provided to allow access tothe excavation chamber when not under pressure. Penetrating thestiffener ring 17 is the main water supply pipe 59 providing water tothe chamber for the hydraulic excavation process The second tube 12,extending from its forward sealing end 61 to its tail end 62, is madeout of strong durable material like steel, the outside shape of whichconforms exactly with the outer shape of the leading tube 11. The firstand second tubes can move independently of each other, a rubber typeseal 63 being provided at the forward end of the second tube 12. Sealingis accomplished by compressing the seals 63 perpendicular to the sealingface with a ring plate 64 by means of bolts (not shown). The second tube12 is strengthened by stiffener rings 65 which carry several jackingmechanisms 66 and 67. Further jacking mechanisms 68 are installedbetween the stiffener ring 17 of the leading tube and the stiffener ring65 of the second tube.

Projecting rearwards from the second tube 12 is the third tube or innerslip-form 13 extending from its forward end 69 to its tail end 70(FIGURE 2). The front part consists of several short sections 71, madeout of strong durable material like steel, overlapping each other atjoints 72 and strengthened by stiffener rings 73. The various sections71 are connected by hydraulic or screw jacks 74 thus allowing relativeadjustment of the sections. At the forward end 69 quick couplings 75engage the piston rods 76 of hydraulic jacks 67. Between the tail end 62of the second tube and the forward end 69 of the third tube is abulkhead ring 81 which is attached to the piston rods 82 of hydraulicjacks 66. Rough timber boards 83, forming a tight fit between the secondand third tubes 12 and 13, are secured tothe bulkhead ring 81 andconstitute the end form for the concrete lining. Shortly afterconcreting is completed the bulkhead ring and timber boards areretracted in readiness for further concreting. Several air pipes 84 withrubber type valves 85 (FIG- URES 5 and 7) are installed in the bulkheadring to permit the application of compressed air between the concreteand bulkhead ring, thereby making removal of the end form easier andcleaner. The rubber valves 85 consist of conical rubber tubes havingperforations 86 along their peripheries and in their centres which openonly when pressure is applied. Further attachments to the bulkhead ring81 are plugged air and water escape openings 87 and a concrete supplyline closure plate 88.

A hydraulic pump 79 rests on beams 78, fixed at their forward ends tothe shield 18 and supported at the other ends on a roller support 77(FIGURES 1 and 5). Also fixed to the shield and supported on the rollersupport 77 is the water supply line 59. A concrete supply line 80 isconnected to the forward section of the third tube 13, the concretebeing supplied by a concrete pump (not shown) rearward of the tunnelmachine.

Attached to the rearmost slip-form section 71 are a plurality of ringsections 89 which are smaller in size than the concrete lining andconsist of an outer tube 90, an inner tube 91, stiffener rings 92 andthermal insulation 93. The said ring sections 89 are held in positionrelative to each other by hydraulic or screw jacks 128 which allowadjustment in alignment of the sections. The joints 94 are sealed by arubber seal band 95 secured to the end of each section 89* by steelbands 96. The ring sections 89 are guided by spacer bars 97 (FIGURE 6)which are off-set in the various ring sections to provide anuninterrupted space 98 between the concrete face and the outer tube 90.The space 98 is sealed at the end of the outer ring 90 by an inflatabletube 99 pressing against the concrete face when under pressure only,pressure being applied through valves 100 connected to the compressedair system. High pressure steam is constantly supplied to the space 98from a steam plant (not shown) through pipe connections 101 anddischarged through pipe connections 102. The rear end of the last ringsection 89 is furnished with a seal ring 103 (similar to the seal 61 ofthe second tube 12) acting against the outer shell 104 of the tail endring section 105 of the third tube 13.

The tail end ring section 105 consists of an outer shell 104, stiffenerrings 106, inner shell 107 and seal 108, which is similar to seal 99.Hydraulic jacks 109 connect the tail end ring section 105 to the lastring section 89.

At the bottom of the concrete lining, and in front of the seal 99 is ascraper 110, collecting the accumulated concrete spallings into thespace 111, from where they can be jetted by nozzles 112 (FIGURE 8)through holes 113 into a chamber 114. The spallings can then be removedafter closing the hole 113 by means of a hydraulic jack 115 and openinga lid 116. A window 117 7 allows inspection of the collecting chamber111.

The water supply pipe 59 and discharge line 21 are supported by rollersupports 118 mounted at suitable intervals on the inner tube 91 of thethird tube 13. The discharge line 21 extends into a collecting chamber119 and is supported on rollers 120 and adjacent to the chamber. Thecollecting chamber 119 has arubber collar 121 at the entrance hole 122and a mouth piece 123 to which a second hydraulic pump 124 is mounted. Afixed discharge line 125leading to a disposal basin outside of thetunnel is mounted to the discharge end of the pump 124. The collectingchamber 119 with second pump 124 are stationary and are relocated insteps equal to one length of discharge line 125 with the advancement ofthe leading tube 11. The water supply pipe 59 is connected with thefixed water supply pipe 126 by a looped hose 127 which is successivelyconnected to new sections of pipe, added to the water supply pipe 126.

Having described the various members of the tunnelling machine, themethod of operation is now explained.

Soil is continuously removed from the excavation face by the cutter ordrilling bit 34 which is able to reach every part of the face throughthe rotary action of ball joint 33 and split shell 38 combined with theaxial move ment of the drilling rod 32. The loosened material drops intoa pool created in front of the shield, 18, the water surface 55 of thepool always being maintained well above the opening 20 by supplyingwater from the water supply pipe 59. Water and exacavated material arewithdrawn by the hydraulic pump 79 and discharged through the dischargeline 21 into the collecting chamber 119 located to the rear of thetunneling machine. A jaw crusher 49 mounted to the rear of the shield 18crushes small boulders and oversize gravel to a size capable of beinghandled by the pump. From the collecting chamber 119 the water-soilmixture is withdrawn by the hydraulic pump 124 and discharged throughdischarge line 125 into a settling tank or basin, preferably locatedoutside the tunnel.

The discharge end of the discharge line 21, following the movement ofthe leading tube 11, travels toward the opening 122 of the collectingchamber 119. When the distance traveled is sufficient to allow theinstallation of a new length of pipe to the stationary discharge line125, the collecting chamber 119 is relocated one step further into thetunnel and the new length is then added to the stationary discharge line125. The pump 79', discharge line 21 and water supply pipe 59 rest onroller supports 77, 118 and 120 to allow independent movement of thevari ous components of the tunnelling machine.

Simultaneously with the excavation operation, the leading tube 11 isadvanced by hydraulic jacks 68 mounted to the rear of stiffener ring 17and acting against stiffener ring 65 of the second tube 12 whichsupports further jacking m'echanisms66 acting through piston rods 82against the bulkhead ring 81 and therefrom against the concrete lining.While the leading tube 11 is advanced, its tail end 15 slides towardsthe seal 61 and on reaching its most advanced position, which is equalto the length of a new section of concrete lining, the excavationoperation is temporarily interrupted to allow retraction of the pistonrods 82 together with bulkhead ring 81 and timber facing 83 to aposition close to stiffener ring 65 of the second tube 12. The end faceof theconcrete lining can then be inspected and cleaned andreinforcement, waterstops and other structural components placed inposition. The reinfor-tkment is supplied in mats with the longitudinalbars projecting through the bulkhead ring 81 to provide sufficient lapfor the following section of concrete lining. The bulkhead ring 81,together with all attachments, is then moved to the forward end 69 ofthe third tube or inner slipform 13 providing a space to be filled withconcrete from the concrete supply line 80. Because of the new locationof the bulkhead ring 81 the closer plate 88, mounted thereto, clears thedischarge end of the concrete supply line 80 and concrete is pumped intothe section 6 behind the bulkhead ring 81. Concrete is delivered to thebottom of the section thereby ensuring that air and water is forced tothe top where it is discharged through an escape opening 87.

mediate installation of the permanent concrete lining Without exposingany soil face, thereby conserving the internal stress pattern of thesurrounding soil, this being of considerable significance in tunnelconstruction. This invention also eliminates the necessity forinstalling costly temporary linings.

After the second tube 12 is moved to its new position, the jackingmechanisms 67 pull the third tube or inner slipform 13 forwardsimultaneously closing the discharge end of the concrete supply line 80.For this operation, pressure is applied to seal 108 and reduced in seal99. The tail end section of the third tube 13 remains fixed to theconcrete lining while seal 1G3 slides along the outer shell 104 of tailend section 105, the hydraulic jacks 109 being'released. Following thismovement the seal 99 is pressurized and the tail end section is advancedby means of hydraulic jacks 109 after depressurizing seal 108.

The space 98 between the outer shell 90 and the face of the concretelining is kept under high pressure equivalent to the soil pressurethrough the medium of the high pressure steam, firstly to support thegreen concrete and secondly to rapidly cure it. The steam is suppliedthrough supply pipes 101, located at the rear end of the third tube 13,and travels forward towards discharge pipes 102, located near theforward end of the outer shell 90, losing heat to the concrete duringits forward motion. With the advancement of the third tube 13 theconcrete is gradually exposed to hotter regions similar to the gradualincrease in temperature used in standard steam curing methods. Thelength of the third tube 13 depends, therefore, on the rate of advanceof the leading tube 11 and the required curing time of the concrete andthe length of the front part of the inner slip-form 13, consisting ofring sections 71, depends on the rate of advance of the leading tube 11and the initial setting time of the concrete.

All component sections of the tunnelling machine are made in shortlengths compared to their diameters to allow small adjustments to bemade in respect to the tunnel axis by means of jacking mechanisms 68,66, 67, 74, 93, 109.

The embodiment of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A tunnelling machine adapted to cut and remove soil or soft rock,support the surrounding soil or soft rock of the unlined bore hole,airtightly isolate the face of the bore hole from the rear of the borehole and provide forms and curing facilities for the permanent concretelining as the tunnelling machine moves forward, the said tunnellingmachine comprising a rigid leading tube shaped to the outside dimensionsof the permanent concrete tunnel lining and furnished with a cuttingedge at its front end, a second rigid tube shaped to the same dimensionsslidably overlapped at its forward end by the tail end of the saidleading tube and extending rearwardly beyond the front face of thepermanent concrete tunnel lining providing temporary support for thesurrounding soil or soft rock of the bore hole, a third rigid tubeshaped to and constituting a slipform for the permanent concrete tunnellining projecting forwardly from the front face of the said concretetunnel lining and extending rearwardly into the finished lined tunnel atwhich the rearward portion is slightly smaller in its cross-sectionalarea thus providing a space between the inner face of the said concretetunnel lining and the said slip-form for injecting high pressure steamas a curing agent, a rigid bulkhead ring slidably located between therear end of the second tube and the forward end of the third tubeconstituting a form for the front face of the permanent concrete tunnellining and providing a bearing surface for the jacking mechanisms afterthe said space is filled with concrete, a plurality of jackingmechanisms for the advancement of the second tube mounted periphericallythereon and detachably connected to and bearing on the said bulkheadring, another plurality of jacking mechanisms for the advancement of theleading tube peripherically mounted thereon and bearing on the secondtube while the latter is held in place by the first mentioned jackingmechanisms, a further plurality of jacking mechanisms for theadvancement of the third tube, detachably connected thereon andsupported by the second tube, a closed airtight shield detachablymounted near the tail end of the leading tube isolating the face of thebore hole from the rearward portion of the tunnel, a variety of miningequipment mounted to and penetrating the said shield to cut soil andsoft rock in front of the said shield, a hydraulic dredging mechanism,connected to a rigid pipe penetrating and advancing with the saidshield, a collecting hopper attached to a second pump located rearwardlyfrom the tail end of the third tube receiving the efiluent from thefirst pump the second pump being connected with a stationary dischargeline leading to the disposal facilities, a water supply pipe rigidlyconnected to the leading tube and flexibly connected to a stationaryWater supply pipe rearwards of the third tube supplying water to thebore hole forward of the said shield for hydraulic removal of theexcavated material, and a concrete supply line connected to the frontend of the third tube for conveying concrete to the space behind thesaid bulkhead ring.

2. A tunnelling machine in accordance with claim 1, wherein miningequipment is detachably and movably mounted to the rear of andpenetrating the shield by means of airtight ball joints.

3. A tunnelling machine in accordance with claim 1, wherein movable highpressure water nozzles are installed on the shield and project into thespace in front of the shield for the loosening of the soil by means ofwater jets.

4. A tunnelling machine in accordance with claim 1, wherein an airtightcover operated by jacking mechanisms is slidably attached to the frontface of the shield by means of guide rails to form an air lock for theremoval of the mining equipment.

5. A tunnelling machine in accordance with claim 1, wherein theslip-joint, is furnished with a rubber like seal ring preferably locatedat the front end of the second tube bearing on the inner face of thetail end of the leading tube.

6. A tunnelling machine in accordance with claim 1, wherein the leadingtube has air or water nozzles connected to the air or water systempenetrating the shield from the rear close to the entrance to thedischarge pipe and so directed as to agitate the settled excavatedmaterial in front of the said entrance to the discharge pipe.

'7. A tunnelling machine in accordance with claim 1, wherein a portionof the third tube has the means for circulating high pressure steam fromthe rear end of the said portion to the front end of the said portion.

8. A tunnelling machine in accordance with claim 1,

wherein the tail end of the third tube has a seal ring,

preferably an inflatable rubber-like tube, confined on three sides bysteel plates and pressing with its fourth side against the finishedconcrete lining to prevent the high pressure steam from escaping to therear.

9. A tunnelling machine in accordance with claim 1, wherein all tubesconsist of short sections slidably and airtightly overlapped andconnected by a plurality of jacking mechanisms to allow an adjustment inalignment relative to the tunnel aXis.

10. A tunnelling machine in accordance with claim 1, wherein the thirdtube has means for collecting and removal of laitance in front of theseal at the tail end of the third tube.

11. A tunnelling machine in accordance with claim 1, wherein a crusheris installed in line with the discharge line and mounted to the rear ofthe discharge opening in the shield.

12. A tunnelling machine in accordance with claim 1, wherein thebulkhead ring is furnished at its forming face with removable timberboards fitting between the inner face of the tail end of the second tubeand the outer face of the forward end of the third tube.

13. A tunnelling machine in accordance with claim 1, wherein thebulkhead ring has means for allowing the installation of structuralcomponents such as reinforcement and water stops.

14. A tunnelling machine in accordance with claim 1, wherein thebulkhead ring has means to force air between the front face of theconcrete and forming face of the bulkhead ring to aid the advancement ofthe bulkhead ring.

15. A tunnelling machine in accordance with claim 1, wherein thebulkhead ring is furnished with a sliding gate located in front of thedischarge end of the concrete supply line, closing when the third tubeadvances and opening when the bulkhead ring advances.

16. A tunnelling machine in accordance with claim 1, wherein the portionof the third tube adapted for curing the concrete lining has a thermalinsulation.

17. A tunnelling machine in accordance with claim 1, wherein the shieldhas detachable high pressure resistant windows for viewing the space infront of the shield from the rear of the shield.

18. A tunnelling machine in accordance with claim 1, wherein the shieldhas movable high pressure resistant spotlights to illuminate the spacein front of the shield, the said spotlights being operated from the rearof the shield.

References Cited UNITED STATES PATENTS 360,959 4/1887 Greathead 61-.85

428,021 5/1890 Rothwell l86 438,509 10/ 1890 Vering 6184 512,037 1/1894Kraus 62 X 748,809 1/1904 Stone 6185 1,026,412 4/1912 Stone 61-85 XFOREIGN PATENTS 620,764 11/ 1935 Germany. 443,158 2/ 1936 Great Britain.

ERNEST R. PURSE'R, Primary Examiner.

1. A TUNNELLING MACHINE ADAPTED TO CUT AND REMOVE SOIL OR SOFT ROCK,SUPPORT THE SURROUNDING SOIL OR SOFT ROCK OF THE UNLINED BORE HOLE,AIRTIGHTLY ISOLATE THE FACE OF THE BORE HOLE FROM THE REAR OF THE BOREHOLE AND PROVIDE FORMS AND CURING FACILITIES FOR THE PERMANENT CONCRETELINING AS THE TUNNELLING MACHINE MOVES FORWARD, THE SAID TUNNELLINGMACHINE COMPRISING A RIGID LEADING TUBE SHAPED TO THE OUTSIDE DIMENSIONSOF THE PERMANENT CONCRETE TUNNEL LINING AND FURNISHED WITH A CUTTINGEDGE AT ITS FRONT END, A SECOND RIGID TUBE SHAPED TO THE SAME DIMENSIONSSLIDABLY OVERLAPPED AT ITS FORWARD END BY THE TAIL END OF THE SAIDLEADING TUBE AND EXTENDING REARWARDLY BEYOND THE FRONT FACE OF THEPERMANENT CONCRETE TUNNEL LINING PROVIDING TEMPORARY SUPPORT FORTHESURROUNDING SOIL OR SOFT ROCK OF THE BORE HOLE, A THIRD RIGID TUBESHAPED TO AND CONSTITUTING A SLIP FORM FOR THE PERMANENT CONCRETE TUNNELLINING PROJECTING FORWARDLY FROM THE FRONT FACE OF THE SAID CONCRETETUNNEL LINING AND EXTENDING REARWARDLY INTO THE FINISHED LINES TUNNEL ATWHICH THE REARWARD PORTION IS SLIGHTLY SMALLER IN ITS CROSS-SECTIONALAREA THUS PROVIDING A SPACE BETWEEN THE INNER FACE OF THE SAID CONCRETETUNNEL LINING AND THE SAID SLIP-FORM FOR INJECTING HIGH PRESSURE STEAMAS A CURING AGENT, A RIGID BULKHEAD RING SLIDABLY LOCATED BETWEEN THEREAR END OF THE SECOND TUBE AND THE FORWARD END OF THE THIRD TUBECONSTITUTING A FORM FOR THE FRONT FACE OF THE PERMANENT CONCRETE TUNNELLINING AND PROVIDING A BEARING SURFACE FOR THE JACKING MECHANISM AFTERTHE SAID SPACE IS FILLED WITH CONCRETE, A PLURALITY OF JACKINGMECHANISMS FOR THE ADVANCEMENT OF THE SECOND TUBE MOUNTED PERIPHERICALLYTHEREON AND DETACHABLY CONNECTED TO AND BEARING ON THE SAID BULKHEADRING, ANOTHER PLURALITY OF JACKING MECHANISMS FOR THE ADVANCEMENT OF THELEADING TUBE PERIPHERICALLY MOUNTED THEREON AND BEARING ON THE SECONDTUBE WHILE THE LATTER IS HELD IN PLACE BY THE FIRST MENTIONED JACKINGMECHANISMS, A FURTHER PLURALITY OF JACKING MECHANISMS FOR THEADVANCEMENT OF THE THIRD TUBE, DETACHABLY CONNECTED THEREON ANDSUPPORTED BY THE SECOND TUBE, A CLOSED AIRTIGHT SHIELD DETACHABLYMOUNTED NEAR THE TAIL END OF THE LEADING TUBE ISOLATING THE FACE OF THEBORE HOLE FROM THE REARWARD PORTION OF THE TUNNEL, A VARIETY OF MININGEQUIPMENT MOUNTED TO AND PENETRATING THE SAID SHIELD TO CUT SOIL ANDSOFT ROCK IN FRONT OF THE SAID SHIELD, A HYDRAULIC DREDGING MECHANISM,CONNECTED TO A RIGID PIPE PENETRATING AND ADVANCING WITH THE SAIDSHIELD, A COLLECTING HOPPER ATTACHED TO A SECOND PUMP LOCATED REARWARDLYFROM THE TAIL END OF THE THIRD TUBE RECEIVING THE EFFLUENT FROM THEFIRST PUMP THE SECOND PUMP BEING CONNECTED WITH A STATIONARY DISCHARGELINE LEADING TO THE DISPOSAL FACILITIES, A WAER SUPPLY PIPE RIGIDLYCONNECTED TO THE LEADING TUBE AND FLEXIBLY CONNECTED TO A STATIONARYWATER SUPPLY PIPE REARWARDS OF THE THIRD TUBE SUPPLYING WATER TO THEBORE HOLE FORWARD OF THE SAID SHIELD FOR HYDRAULIC REMOVAL OF THEEXCAVATED MATERIAL, AND A CONCRETE SUPPLY LINE CONNECTED TO THE FRONTEND OF THE THIRD TUBE FOR CONVEYING CONCRETE TO THE SPACE BEHIND THESAID BULKHEAD RING.